Wire harness assembly has long been a labor intensive exercise which has not fully benefited from integrated data management methods due to long-standing mindsets and formidable obstacles. Wire harness assembly personnel have selected, measured, cut, crimped, bent, labeled, and finally placed, connected, and tied tens, and sometimes hundreds, of individual wires of varying lengths, gauges, and types to form a completed wire harness. If even a single wire in the harness is flawed, the harness may have to be repaired or discarded. Over the years, numerous inventions have attempted to automate some or all of wire harness assembly, with varying degrees of success. Some inventions have focused on separately preparing wire circuits (i.e., the individual wire segments with terminals) apart from the wire harness assembly process. In automated wire circuit preparation inventions, machines are used to select, measure, and crimp roll wire into wire circuits, and then other means are used to transport the circuits to an assembly station. The individual wire circuits are sometimes stored on reelettes or held by clamps, but these methods have inefficiencies and complexities that have long needed improvement. Their complex structures, difficulty in adapting to varying wire circuit specifications, expense of acquisition, use, and maintenance have long needed to be improved. For example, winding wire circuits onto reelettes may introduce anomalous spring tension and irregular bends. Thus, retrieval systems must either have additional complexity to adapt to the varying wire circuit lengths based on unintended bends and spring tension, or risk failures to retrieve some wire circuits. Winding wire circuits onto reelettes may also result in plastic deformation of metal wire. This work hardening may cause immediate wire failure, or may leave a latent defect. The circuit may pass its initial continuity test, but later fail well before its design life due to the residual stress. Further, the winding, storage, and retrieval systems must consistently secure each wire circuit's ends when the circuit lengths can vary due to anomalies introduced by the winding process itself.
Other inventions do not wind the wire circuits; rather, they use clamps to hold each outstretched circuit. This requires much more storage space than a reelette because of the need to accommodate the full length of outstretched wires, isolate each circuit, and provide separation distance between circuits' clamps. The relatively low storage density for the wire circuits can force increased workspace areas, with corresponding increases in overhead costs. Positioning equipment must precisely place the wire circuit for proper clamping, and the clamps must hold the wire circuit securely. In case of system misalignment or error, the clamps may damage circuit ends when the circuit is clamped or retrieved. Because the number of clamps is directly proportional to the number of circuits to store or transport, the quantity of clamps brings a corresponding number of mechanical failures. To prevent costly failures, operators must incur the costs of monitoring, repairing, and replacing the clamps. Further, clamps may fail to successfully grip one or more of the circuit's ends. In such cases, operating machinery may become fouled by untethered wire circuits.
When wire circuits are prepared apart from the wire harness assembly area, the wire circuits must be moved to the assembly station. The wire circuits can be transported singly or in batches, but each circuit must be uniquely identified so that it can be properly processed. Existing systems suffer from unnecessary complexities and limitations in maintaining or transferring the data, as well as in effectively presenting the wire circuits in assembly order to a human or machine.
The systems and methods of the present invention overcome many of the problems and limitations of the prior art. Furthermore, the addition of the double buffer assembly increases the accuracy, speed, and efficiency of the invention as described in the U.S. Provisional Application, Ser. No. 61/381,626, of which this application continues in part.